1. Field of the Invention
The present invention relates to a new and improved method of oxidizing phenyl phosphonous dihalide.
2. The Prior Art
Phenyl phosphonous dihalides are commercially available. Various methods of oxidizing alkyl and aryl phosphonous dihalides have been described in the prior art.
Two methods of oxidizing alkyl phosphonous dihalides are disclosed in U.S. Pat. No. 3,829,480. In that patent a recycle method for oxidizing alkyldihalogenphosphines to the oxides is achieved by the reaction, ##STR2## wherein the oxygen donor is prepared by the reaction, ##STR3## wherein R is any alkyl group and X is any halide. This method yields by-products in contrast to the method of the present invention.
U.S. Pat. No. 3,829,480 also discloses prior art techniques wherein direct oxidation is utilized. According to the patent, however, high pressure and pure starting materials are necessary to carry out such an oxidation process. Accordingly, that direct oxidation method is distinguished from the method of the present invention.
A method of preparing cycloalkane phosphonyl dichlorides is described in U.S. Pat. No. 2,772,308. The method is conducted according to the following reaction scheme: ##STR4## wherein R is a cycloalkane.